Multi-layer laminated boards which may be used as printed wiring boards, which are utilized as components in various electrical and electronic devices, many times possess disadvantageous properties. A major problem which is attendant with many of these laminates which are made of multi-layer substrates is the dimensional stability of the inner layers of the composite board. For example, a multi-layer board may consist of up to 20 layers of substrate materials. When processing these inner layers to form the desired board substrate, the layers are subjected to a thermal stress. During this thermal stress, the inner layers may expand or contract. For example, when utilizing a glass cloth such as a fiberglass cloth, the cloth will exert an effect on the dimensional stability of the inner layers. In this respect, a glass cloth which will expand more than 0.0005 inch/inch will cause registration problems of the pads in the various layers, said poor registration resulting in the inability to connect the inner layers which is cause for either failure or rejection.
Another area in which thermal expansion plays an important role is that of carriers for silicon chips which are used in dual in-line packages for integrated circuitry. Heretofore, silicon chips have been mounted on a chip carrier such as ceramics or plastics which in turn has been mounted on a chip carrier substrate or circuit board. In some instances, it is important that the electrical connection between the chip carrier and the chip carrier substrate is hermetically sealable and possess the ability of being able to withstand temperature cycling. The reason for this is that when the package is subjected to temperature extremes, the solder joints may fracture due to varying thermal expansion properties of the different materials involved and an electrical open core occurs. This is due to the stress which is produced and which is exerted on the solder joints which connect the materials inasmuch as the materials expand and contract at different rates. In order to overcome this problem, it is necessary to utilize a chip carrier or a chip carrier substrate which will have the necessary rate of thermal expansion to insure that the solder joints will not fracture during thermal cycling.
It is therefore readily apparent that if a material can be obtained which possesses a dimensional stability, the material may be used as a component in preparing multi-layer laminates which may, in turn, form the substrate for a printed wiring board and for chip carrier substrates. As will hereinafter be shown in greater detail, such a hydrid glass cloth may be obtained which will possess the desired dimensional stability by combining fiberglass and a second material which possesses a desired co-efficient of thermal expansion.